The objective of this proposal is to compare the effect of butterfat, safflower oil, and fish oil on BP regulation in humans. We hypothesize that fish oil will lower BP to the greatest extent, while butterfat and safflower oil will not differ from one another. Ca2+ efflux from RBC membranes is expected to be higher, and platelet [Ca2+]i is expected to be lower in cells harvested from humans during the fish oil-based diet than during either the butterfat or safflower oil phases.